Detecting the presence of a human being when he or she cannot be seen or heard is an ongoing issue in many situations including disaster relief, hostage crises, kidnapping, human trafficking, correctional facilities, etc. In the case of detecting the presence of a human being in a vehicle, known systems and methods exist that detect vibrations due to the human heartbeat without having to open the vehicle. See, e.g., U.S. Pat. Nos. 6,370,481, and 7,019,641. However, these known systems and methods involve the use of sensors that have to be in physical contact with the vehicle and other noise subtraction sensors which are placed on the ground around the vehicle. Thus, the known systems and methods involve the use of sensors which have to be in physical contact with the object to be investigated.